The volume at which an audio file, including those audio files associated with videos, is output may be adjusted to increase the likelihood that a listener will hear and enjoy the playback of the audio file. The volume of an audio file may be adjusted manually. However, manual adjustments generally change the volume in a uniform manner across the entire spectrum such that the volume of audio signals having frequencies in which the listener is less interested is adjusted by a proportional amount to the volume of audio signals having different frequencies in which the listener is more interested. For example, manual volume adjustments may proportionately increase both the audio signals generated by the drums in which the listener is less interested and the audio signals generated by a guitar in which the listener is more interested.
In order to reduce the requirement for input from the listener, techniques have been developed to adjust the volume at which an audio file is output based on context, such as based upon the background noise, such as based upon the spectral content of the background noise, and/or parameters of the audio file, such as the genre of the audio file. While volume adjustments based on the context may reduce manual involvement, volume adjustments based upon the context may uniformly adjust the volume for all audio signals regardless of their frequency or may only adjust the volume for audio signals within a limited frequency range that includes the dialogue of the audio file. In either instance, for an audio file that includes contributions from different instruments, the output of the audio file may still be such that the contributions of at least some of the instruments are difficult to hear, at least in noisy environments.
At least some audio files are originally mixed by a producer who determines the frequencies of audio signals to emphasize and deemphasize during different portions of the playback of the audio file. Typically, a producer mixes the audio file in a quiet environment and in accordance with the preferences of the producer. A listener, however, may have different preferences than the producer in terms of the frequencies of the audio signals to emphasize and deemphasize. Additionally, the listener may playback an audio file in a different environment than that in which the audio file was originally mixed, such as by playing back the audio file in a noisy environment. Thus, the manner in which the audio file was originally mixed may not be entirely applicable to the environment in which the audio file is played back. However, manual remixing of an audio file to differently emphasize or deemphasize frequencies of the audio signals or to otherwise adapt the audio file to the environment in which the audio file is being played back may be time consuming and may require at least some degree of experience.
In addition to or instead of adjusting the volume at which an audio file is played back, the listener may sometimes also control the level of audio dynamic compression. With respect to Dolby digital files, for example, a listener may set the level of compression with the Dolby system then maintaining dialogue from the audio file at the original level of compression, but otherwise adjusting the audio dynamic range in accordance with the level of compression established by the listener. Nonetheless, such control of the level of audio dynamic compression of an audio file again requires manual input that may be time consuming and that may require some degree of experience to achieve the desired result.